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Microgravity Acceleration Measurement System (MAMS)
05.16.12
Scientists and payload developers can get more information on International Space Station research facilities by contacting the ISS Payloads Office or at 281-244-6187.

Overview | Description | Applications | Operations | Results | Publications | Images

Facility/Payload Overview

Brief Facility Summary

Microgravity Acceleration Measurement System (MAMS) studies the small forces, or vibrations and accelerations, on the International Space Station (ISS) that result from the operation of hardware, crew activities, dockings and maneuvering. Results are used to generalize the types of vibrations affecting vibration-sensitive experiments. Investigators seek to better understand the vibration environment on the space station.

Facility Manager(s)

  • William Foster, , Glenn Research Center, Cleveland, OH, United States

    • Co-Facility Manager(s)

    Information Pending

    Facility Developer

    ZIN Technologies Incorporated, Cleveland, OH, United States

    Sponsoring Agency

    National Aeronautics and Space Administration (NASA)

    Expeditions Assigned

    1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19/20, 21/22, 23/24, 25/26, 27/28, 29/30, 31/32, 33/34

    Previous ISS Missions

    MAMS has been operating on ISS since Expedition 2.

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    Facility/Payload Description

    Facility Summary

    • Microgravity Acceleration Measurement System (MAMS) measures vibratory and quasi-steady acceleration within the United States Laboratory Module on the International Space Station(ISS).


    • Vibrations exist on the ISS from a variety of sources, such as equipment operation, life-support systems, crew activities, aerodynamic drag, gravity gradient, rotational effects and the vehicle structural resonance frequencies.


    • The quasi-steady acceleration is caused by forces from aerodynamic drag, gravity gradient effects, centripetal (rotational) motion, spacecraft propulsion, and vehicle orientation control actions.


    • Two sensors, the Orbital Acceleration Research Experiment (OARE) Sensor Subsystem (OSS) and the High Resolution Accelerometer Package (HiRAP), monitor these disturbances. The OARE OSS measures low range frequency (up to 1 Hz). The HiRAP characterizes the ISS vibratory environment from 0.01 Hz to 100 Hz.

    Description

    Changes in acceleration and moving mechanical parts cause small vibrations to move through the Station's structure. These disturbances occur within the frequency range of 0.01 to 300 Hz. Microgravity Acceleration Measurement System (MAMS) is one of two experiments onboard that measures and records the vibrations. The Space Acceleration Measurement System-II (SAMS-II) measures vibrations from vehicle acceleration, systems operations, and crew movements. MAMS complements this data by recording accelerations caused by aerodynamic drag and ISS movements caused by small attitude adjustments, gravity gradient, and the venting of water. These quasi-steady state accelerations occur in the frequency range below 1 Hz. MAMS consists of a low-frequency triaxial accelerometer, the Miniature Electro-Static Accelerometer (MESA), a high-frequency accelerometer, the High-Resolution Accelerometer Package (HiRAP), and associated computer, power, and signal processing subsystems contained within a Double Middeck Locker enclosure.

    MESA consists of a hollow, cylindrical flanged mass, two X-axis forcing electrodes, an outer cylindrical proofmass carrier with Y- and Z-axis electrodes, and control electronics enclosed in a protective case. Static electricity forces the sensor proofmass to remain centered between the electrodes. The "sensed" acceleration is proportional to the voltage needed to keep the sensor centered.

    MESA is mounted on a Bias Calibration Table Assembly (BCTA), a mechanism allowing on-orbit calibration. Calibration is used to remove electronic bias from the "sensed" acceleration.

    Currently MAMS is only operated during special events such as an International Space Station (ISS) reboost and spacecraft dockings.

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    Operations

    Facility Operations

    MAMS measures subtle accelerations that affect only certain types of experiments and is not operational all the time. MAMS operates from the Glenn Research Center Telescience Support Center at appropriate times. After initial installation on the Station, MAMS requires a minimum of four days of continuous operation to characterize the sensors' performance and to calculate any sensor bias. MAMS was set up and activated on May 8, 2001, and continued operation for eight days to collect data during normal Station operations. Since then, it has been reactivated several times to record dockings and other disturbances. Multiple calibrations taken over long periods of operation can be used to further improve the accuracy of MAMS data.

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    Results/More Information

    One of the major goals of the ISS is to provide a quiescent low-gravity environment to perform fundamental scientific research. However, small disturbances aboard the ISS impact the overall environment in which experiments are being performed. Such small disturbances need to be measured in order to assess their potential impact on the experiments. MAMS is used on board the ISS to do just that.

    MAMS data have been analyzed to examine the quasi-steady regime on station with a frequency below 0.01 Hz. These are related to aerodynamic drag, gravity gradient and rotational effects, venting of air or water, and appendage movement, such as that of the solar arrays and antennas. Characteristics were found in the data that were unexplainable for a short period of time. Analysts determined that the movement of the Ku-band antenna was the source of the unusual characteristics in the quasi-steady data collected by MAMS. (A Ku-band antenna is used to transmit payload science data and video from ISS to Earth.) The correlation was made after comparing the data with real-time observations from ISS (DeLombard et al. 2002, 2004).

    A special study using MAMS data was performed by ISS science officer Don Pettit during Expedition 6 as a part of Saturday Science. Pettit examined the motion of air bubbles in water to see how it correlated with quasi-steady accelerations, vibrations that are at or below a frequency of 0.01 Hz for a period greater than 100 seconds (DeLombard et al. 2005).

    MAMS is currently being activated intermittently to meet operational requests for data during major mission events such as dockings by Soyuz and Progress vehicles. (Evans et al. 2009)

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    Availability

    Information Pending

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    Related Web Sites
  • Microgravity Acceleration Measurement System
  • Principal Investigator Microgravity Services
  • ISS Research Project-MAMS

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    Publications

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    Related Publications

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    Images

    imageNASA Image: ISS003E6010 - Culbertson poses with MAMS hardware in the U.S. Laboratory during Expedition 3.


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    imageNASA Image: ISS007E06980 - Back-dropped by the blackness of space and Earth's horizon, an unmanned Progress supply vehicle approaches the ISS during Expedition 7. Inset image shows microgravity acceleration data provided by the MAMS hardware during a Progress docking with ISS.


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    imageNASA Image: ISS013E65575 - Shown is the Microgravity Acceleration Measurement System (MAMS) used to measure acceleration during specific ISS operations. MAMS is located in EXPRESS Rack 1 in the U.S. Laboratory.


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    Information provided by the investigation team to the ISS Program Scientist's Office.
    If updates are needed to the summary please contact JSC-ISS-Program-Science-Group. For other general questions regarding space station research and technology, please feel free to call our help line at 281-244-6187 or e-mail at JSC-ISS-Payloads-Helpline.
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